Creatine is present in vertebrate muscle tissues, which has the function of promoting muscle growth and building up health. Creatine can be used as a food additive, and formulations containing creatine have become an essential everyday food additive of sportsman in many countries of the world, especially in Europe and America. It also becomes more and more popular among sports enthusiasts. The need of creatine used as food additives in China is also increasing.
Conventionally, the preparation of creatine involves extraction from biological raw materials such as muscle scraps. However, such a method is not cost effective and the use of such a source is not very sanitary. Currently, creatine is mainly prepared by chemical synthesis, i.e. through reaction of cyanamide with N-methylglycine (sarcosine). However, N-methylglycine is a very expensive raw material, moreover, a satisfactory yield can not be achieved. Chinese Patent application CN 1140707A filed by the SKW Trestberg Corporation Ltd. discloses a process for preparing creatine or creatine-monohydrate, which is aimed to achieve a commercially acceptable yield and a higher purity. In this process, cyanamide is reacted with sodium N-methylglycinate or potassium N-methylglycinate in water or in a mixture of water and an organic solvent at a temperature of 20.degree. C. to 150.degree. C. and pH of 7 to 14. However, the cost by using this method is very high, furthermore, harmful impurities such as cyanide and/or ammonia may be present in the product. Briefly speaking, known method for preparation of creatine is not satisfactory.